The conscious access hypothesis: origins and recent evidence

EEG microstates as a tool for studying the temporal dynamics of whole-brain neuronal networks: A review

“…Only one such episode of coherent activity is thought to occur at any given time, and episodes are separated by sharp transitions. Similar models were proposed by Baars and colleagues (Baars, 1997;Baars, 2002a), who concluded the following: "If conscious events are associated with global states of the dynamic core, such that only one such event can prevail at any one time, it follows that global states of the core appear serially" (Seth and Baars, 2005). In accordance with the neuronal workspace model-and with Dietrich Lehmann's theory that EEG microstates represent the basic building blocks of consciousness ("atoms of thoughts") (Koukkou and Lehmann, 1987;Lehmann, 1992; Lehmann et al, 1998)-we proposed that EEG microstates are the "electrophysiological correlates of a process of global, 'conscious' integration at the brain scale level".…”

“…In the aforementioned microstate analysis procedure, the crucial a priori assumption Any sufficient change in one of these sub-states will thus simply result in a new global state, both in terms of its potential functional significance and physiological manifestation. This argument corresponds to functional theories that assume that only one global functional state occurs at any given moment in time (Baars, 2002a;Efron, 1970). Similar arguments are used to justify spatial clustering procedures in other brain imaging modalities such as fMRI (Cordes et al, 2002), in intracranial animal studies (Stopfer et al, 2003), and even in vitro (Wagenaar et al, 2006), embedding the application of the microstate methodology into an overarching framework used to explain particular functional features of brain activity (discussed in detail in Section 5).…”

How conscious experience and working memory interact

“…Could that be a coincidence, or are conscious contents needed for WM? Several theorists now suggest an active role for conscious events in working memory [1][2][3][4][5][6].…”

“…Global Workspace theory (GW) suggests that conscious experiences involve widespread distribution of focal information, to recruit neuronal resources for problem solving [1,2,7,8]. Brain studies suggest that the sensory and frontolimbic cortices could serve such a distributive/ integrative function, consistent with their thalamocortical connectivities [2,9 -11].…”

“…The IDA model can elucidate these functions, as well as executive control of working memory. This provides a functioning model of how conscious events may help to accomplish cognitive tasks [2].…”